Carbonated beverage can and method for producing a carbonated beverage can

Abstract

The present invention resides in a method for producing a carbonated beverage can which has acceptable creep, modulus and yield strength values, which comprises a can body, which is made up of a core of a thermoplastic material, at least two layers of non-fibrous, extruded polyolefin film which has either been monoaxially stretched or biaxially stretched, [and which are wrapped around the core singularly or in plys at opposite plus/minus angles in relationship to each other to yield disproportionate stress resistance vectors for hoop and axial stresses present in said body at a 2:1 ratio] one layer of which is wrapped around said core singularly or in plys at an angle with respect to said core of from about +60° to about +80° and the other of said two layers is wrapped around said core singularly or in plys at an angle with respect to said core of from about -60° to about -80°, an adhesive layer which is placed between the core and the layers of polyolefin in order to adhere the layers to the core as well as the layers to themselves and at least one layer of a barrier material, and ends which are attached [by some suitable method] to the can body.

We claim: 
     
       1. A thin-wall carbonated beverage can with acceptable creep, modulus and yield strength values, which comprises: a can body which is less than 80 mils thick, which comprises: a core of a thermoplastic material; at least two layers of a film or sheet of an extruded non-fibrous polyolefin material, both of which have been either monoaxially stretched or biaxially stretched to a tensile yield strength of above 8,000 psi in any one direction, and to an elastic modulus of above 400,000 psi in any one direction, the first layer of which is wrapped around said core singularly or in plys at an angle from the axial direction of said core of greater than 0° and less than +90° and the second layer of which is wrapped around said core singularly or in plys at an angle from the axial direction of said core of the negative value of the angle of the first layer;   an adhesive layer which is placed between said core and said layers of polyolefins in order to adhere said layers to said core as well as said layers to themselves; and   at least one layer of barrier material which is either in said core or contiguous to either said core, said layers of polyolefin or said adhesive layer; and     ends which are attached to said can body.   
     
     
       2. The carbonated beverage can of claim 1, wherein said core is made of a polyolefin. 
     
     
       3. The carbonated beverage can of claim 1, wherein said core is made of extruded polypropylene or coextruded polypropylene layer, tie layer and barrier layer. 
     
     
       4. The carbonated beverage can of claim 1, wherein said two layers of polyolefin which have each been monoaxially stretched, are wrapped around said core. 
     
     
       5. The carbonated beverage can of claim 1, wherein the first of said two layers which have been biaxially stretched is wrapped around said core singularly or in plys at an angle from the axial direction of said core of from about +60° to about +80° and the second of said two layers is wrapped around said core singularly or in plys at an angle from the axial direction of said core of the negative value of the angle of the first layer. 
     
     
       6. The carbonated beverage can of claim 1, wherein the first of said two layers which have been monoaxially stretched is wrapped around said core singularly or in plys at an angle from the axial direction of said core of from about +50° to about +60° and the second of said two layers is wrapped around said core singularly or in plys at an angle from the axial direction of said core of the negative value of the angle of the first layer. 
     
     
       7. The carbonated beverage can of claim 1, wherein said adhesive contains polybutene-1, or copolymers thereof. 
     
     
       8. The carbonated beverage can of claim 1, wherein said adhesive is contiguous to at least one side of said polyolefin layers. 
     
     
       9. A thin-wall carbonated beverage can with acceptable creep, modulus and yield strength values, which comprises: a can body which is less than 80 mils thick, which comprises: a core of coextruded non-fibrous polypropylene layer, tie layer and barrier layer; two layers of polypropylene, both of which have been monoaxially stretched to a tensile yield strength of above 8,000 psi in any one direction and to an elastic modulus of above 400,000 psi in any one direction, the first layer of which is wrapped around said core singularly or in plys at an angle from the axial direction of said core of from about +50° to about +60° and the second layer of which is wrapped around said core singularly or in plys at an angle from the axial direction of said core of the negative value of the angle of the first layer; and   an adhesive layer which is contiguous to at least one side of said polypropylene layers in order to adhere said layers to said core as well as to said layers themselves; and     ends which are attached to said can body.   
     
     
       10. The carbonated beverage can of claim 9, wherein said adhesive contains polybutylene-1, or copolymers thereof. 
     
     
       11. A method of manufacturing a carbonated beverage can which has acceptable creep, modulus and yield strength values, which comprises the steps of: manufacturing a core of a thermoplastic material;   extruding at least two layers of a non-fibrous polyolefin film;   stretching both of said two layers either monoaxially or biaxially;   wrapping said layers of polyolefin film around said core, wherein the first layer of which is wrapped around said core singularly or in plys at an angle from the axial direction of said core of greater than 0° and less than +90° and the second layer of which is wrapped around said core singularly or in plys at an angle from the axial direction of said core of the negative value of the angle of the first layer;   placing an adhesive layer between said core and said layers of polyolefin film in order to adhere said layers to said core as well as said layers to themselves;   placing at least one layer of barrier material either in said core or contiguous to either said core, said layers of polyolefin film, or said adhesive layer, where said core wrapped with said layers of polyolefin film, said adhesive layer and said barrier material layer is a can body; and   attaching ends to said can body.   
     
     
       12. The method of claim 11, wherein said core is made of polyolefin. 
     
     
       13. The method of claim 11, wherein said core is made of extruded polypropylene or coextruded polypropylene layer, tie layer and barrier layer. 
     
     
       14. The method of claim 11, wherein two layers of polyolefin film which have been monoaxially stretched, are wrapped around said core. 
     
     
       15. The method of claim 14, wherein the first of said two layers which have been monoaxially stretched is wrapped around said core singularly or in plys at an angle from the axial direction of said core of from about +50° to about +60° and the second layer of which is wrapped around said core singularly or in plys at an angle from the axial direction of said core of the negative value of the angle of the first layer. 
     
     
       16. The method of claim 11, wherein said adhesive contains polybutene-1. 
     
     
       17. The method of claim 11, wherein said adhesive is contiguous to at least one side of said polyolefin film. 
     
     
       18. The method of claim 17, wherein said core is made of extruded polypropylene or coextruded polypropylene layer, tie layer and barrier layer. 
     
     
       19. The method of claim 17, wherein said two layers of polyolefin film which have each been monoaxially stretched and are wrapped around said can body, are polypropylene. 
     
     
       20. The method of claim 17, wherein the first of said two layers which have been monoaxially stretched is wrapped around said core singularly or in plys at an angle from the axial direction of said core of from about +50° to about +60° and the second of said two layers is wrapped around said core singularly or in plys at an angle from the axial direction of said core of the negative value of the angle of said first layer. 
     
     
       21. The method of claim 17, wherein said adhesive contains polybutene-1. 
     
     
       22. The method of claim 17, wherein said adhesive contains is contiguous to at least one side of said polyolefin film layers. 
     
     
       23. A method of manufacturing a carbonated beverage can which has acceptable creep, modulus and yield strength values, which comprises the steps of: manufacturing a core of polypropylene;   extruding at least two layers of a non-fibrous polyolefin film;   monoaxially stretching said non-fibrous polyolefins film layers;   wrapping said layers of non-fibrous polyolefin film around said core wherein the first layer of which is wrapped around said core singularly or in plys at an angle from the axial direction of said core of greater than 0° and less than +90° and the second layer of which is wrapped around said core singularly or in plys at an angle from the axial direction of said core of the negative value of the angle of said first layer;   placing an adhesive layer between said core and said layers of polyolefin film in order to adhere said layers to said core as well as said layers to themselves;   placing at least one layer of barrier material either in said core or contiguous to either said core, said layers of polyolefin film or said adhesive layer, which said core wrapped with said layers of polyolefin film, said adhesive layer and said barrier material layer is a can body; and   attaching ends to said can body.   
     
     
       24. A method of manufacturing a carbonated beverage can which has acceptable creep, modulus and yield strength values, which comprises the steps of: extruding a core of coextruded polypropylene layer, tie layer and barrier layer;   extruding at least two layers of non-fibrous polypropylene film;   monoaxially stretching said layers of polypropylene film;   wrapping the first of said layers of polypropylene film around said core singularly or in plys at an angle from the axial direction of said core of from about +50° to about +60° and the second of said polypropylene film layers is wrapped around said core singularly or in plys at an angle from the axial direction of said core of the negative value of the angle of said first layer;   placing an adhesive layer contiguous to at least one side of said polypropylene film layers in order to adhere said layers to said core as well as to said layers themselves, where said core wrapped with said layers of polypropylene film, said adhesive layer and said barrier material layer is a can body; and   attaching ends to said can body.   
     
     
       25. The method of claim 24, wherein said adhesive contains polybutene-1 or copolymers thereof.